The overall goal of our research program is to increase understanding of the prevalence, the characteristics, and the outcome of early language delay, so that the mental health and educational handicaps secondary to language delay can be prevented by early identification and remediation. In the first study, we propose an epidemiological survey of 600 2-year old children in order to determine the overall prevalence of expressive language delay, its association with demographic factors, and the distribution of its "subtypes" (e.g, mental retardation, hearing impairment, autism, specific language disability, and specific expressive language delay (SELD). Parents will complete the Language Development Survey (LDS), a vocabulary checklist we have developed, and children will be given the Binet IV Vocabulary subtest. Each child identified as language-delayed by the prevalence survey, and a matched normal comparison group, will be seen for full assessment. In the second study, we propose a longitudinal yearly follow-up to age 7 of 35 children we have been following since the age of 24 to 30 months whom we diagnosed a manifesting specific expressive language delay (SELD) (e.g., normal nonverbal ability, age-adequate receptive language, and significant delay in expressive speech), as well as a matched comparison group of 35 normal children. This research will study the association between SELD and later reading/learning problems. Finally, in the third project, we plan detailed linguistic analysis of the longitudinal language samples we have on these 35 SELD children, in order to further identify those aspects of language in which our SELD children appear to be normal vs. those aspects in which they are showing continued delay.